1. Field of the Invention
This invention relates to a rotary shutter blade driving mechanism for cameras.
2. Description of the Prior Art
There is already proposed (in U.S. Pat. No. 3,672,282) a shutter blade driving unit of the type in which the energy used for operation of the shutter blades is absorbed and accumulated in the unit in the course of deceleration of the blades and such accumulated energy is used for the next operation of the shutter blades. (This type of shutter is hereinafter referred to as an energy absorption type shutter). This shutter blade driving unit, however, has many cam surfaces and locking means, so that it is an extremely complicated mechanism. Further, according to this driving unit, a substantial portion of energy is wasted due to friction loss caused during movement of the blades, so that the deficient energy must be supplied from the outside in the final stroke of the next shutter charge, and hence a large force is suddenly required at the termination of the shutter charge.